溴化汞修饰碳糊氯氮电极的研制

以氯氮与硝酸汞 (2∶ 1)的配位化合物作为电活性物质 ,研制了氯氮 -溴化汞修饰碳糊电极 ,得到了良好的电极响应曲线 ,响应斜率为 5 8.8m V/ p C,线性范围为 5 .0× 10 - 5～ 0 .14 mol/ L ,检出限为 1.0× 10 - 5mol/ L。十多种常见无机离子对电极无干扰。应用该电极可采用直接电位法测定氯氮片含量。     

溴化汞修饰碳糊氯氮Zhuo电极的研制

以氯氮(艹卓)与硝酸汞(2∶1)的配位化合物作为电活性物质,研制了氯氮FDA8-溴化汞修饰碳糊电极,得到了良好的电极响应曲线,响应斜率为58.8 mV/pC,线性范围为5.0×10-5～0.14 mol/L,检出限为1.0×10-5mol/L.十多种常见无机离子对电极无干扰.应用该电极可采用直接电位法测定氯氮(艹卓)片含量.     

大量抗坏血酸存在下多巴酚丁胺的铂电极测定

利用多巴酚丁胺 (1)的盐酸 (或硫酸 )溶液在铂电极上能催化苯胺氧化的性质对其进行了准确定量测定。在含0 .2 0 mol/ L苯胺的 0 .10 mol/ L HCl(或 0 .0 5 mol/ L H2 SO4)溶液中 ,做循环伏安扫描 ,溶液中的苯胺能还原 1的氧化产物 ,而自身变成氧化态 ,利用它可在 0 .34 5 V(SCE)左右产生一对可逆的氧化还原峰以定量测定 1,线性范围为1.1× 10 - 6～ 3.5× 10 - 4 mol/ L ,检测限为 2 .0× 10 - 7mol/ L。在本试验条件下由于测量峰电位存在显著负移 ,即使存在 10 0倍的抗坏血酸亦不会发生干扰。     

一阶导数高速脉冲极谱法用于氯化钠的定量分析

本文研究了一阶导数高速脉冲极谱祛,并将其运用于氯化钠及其制剂的定量分析中。在-0.11V(vs Ag/AgCl)处出现一良好的导数极谱峰,在6.2×10~(-4)～3.1×10~(-3)mol/L范围内,浓度与导数峰电流呈线性关系。检测限为3.1×10~(-7)mol/L。操作简便、快速、灵敏,结果准确。     

比色法测定丁胺卡那霉素、卡那霉素、新霉素和妥布拉霉素

本法是基于五氰亚硝酰铁酸二钠(diso—dium pentacyanonitrosylferrate与脂肪族伯胺和仲胺的Rimini反应,可用以测定丁胺卡那霉素、卡那霉素、新霉素和妥布拉霉素;但对该四个抗生素没有分辨能力。该四种抗生素的浓度与反应后在540nm时的吸收峰值符合Beer定律:其适当浓度分别为2.8×10~(-4)～1.7×10~(-3)mol/L、2.6×10~(-4)～2.0×10~(-3)mol/L、1.7×10~(-4)～1.9×10~(-3)mol/L和2.5×10~(-4)～1.6×10~(-3)mol/L。     

铬(Ⅵ)存在下谷胱甘肽的电化学检测

目的探讨铬 (Ⅵ )与还原型谷胱甘肽 (GSH)之间的作用机制 ,并建立一种GSH的电化学检测方法。方法采用循环伏安法研究GSH与铬 (Ⅵ )相互作用 ,从而影响铬 (Ⅵ )在金电极上的电响应。结果在含 0 .0 0 1mol/LH2 SO4的 0 .1mol/LNaNO3 溶液中铬 (Ⅵ )离子在金电极表面于 +0 .2V(Vs .SCE)有一较强的还原峰 ,当溶液中加入少量GSH时 ,该峰电流下降 ,并且随着GSH的不断加入峰电流逐渐减小 ,在一定的浓度范围内GSH加入量与峰电流的下降呈线性关系 ,据此建立了一种GSH的电化学检测方法 ,其线性范围为 7.0× 10 -8～ 1.0× 10 -9mol/L ,检测限为 1.0× 10 -9mol/L ,RSD为 0 .4 %。结论获得灵敏、简便、快速的间接的GSH电化学分析方法。     

葛根素促进体外培养大鼠颅骨成骨细胞增殖和分化过程中对cAMP/PKA信号通路的影响

目的 研究葛根素对体外培养大鼠颅骨成骨细胞(rats osteoblast,ROBs)增殖和分化及cAMP/PKA信号通路的影响.方法 体外分离培养ROBs,观察不同浓度(1×10-4～1 ×10-8 mol/L)葛根素对ROBs增殖和碱性磷酸酶(alkaline phosphatase,ALP)活性的影响;分析葛根素对骨形态发生蛋白(Bone morphogenetic protein,BMP-2)、Ⅰ型胶原(Col Ⅰ)、成骨特异性转录因子-2(Runx-2)和Oxterix mRNA表达水平的影响;观察1×10-6 mol/L葛根素对BMP-2、Col-Ⅰ、Runx-2、Oxterix、PKA和磷酸化PKA(p-PKA)蛋白表达水平,测定细胞中cAMP的变化.结果 细胞增殖结果显示1×10-7 mol/L ROBs细胞浓度高于对照组,1×10-4 mol/L组ROBs细胞浓度低于对照组(P＜0.01).1×10-5、1×10-6、1×10-7mol/L组ROBs ALP活性均高于对照组(P＜0.05,P＜0.01).1×10-6 mol/L葛根素处理ROBsRunx-2、Oxterix、BMP-2、Col Ⅰ mRNA和蛋白及p-PKA、cAMP表达水平均高于对照组(P＜0.05,P＜0.01).结论 1×10-6 mol/L葛根素为促进ROBs增殖和分化的最适浓度,其可促进体外培养ROBs分化过程中cAMP/PKA信号通路的激活.     

人工培养冬菇菌丝体中抗血栓形成成分的分离和生物学性质

从人工培养冬菇菌丝体中用阳离子交换纤维素层析分离,获得一种具有抗血栓形成作用的蛋白质,分子量为1.75×10~4u,等电点为4.3,给大鼠iv10~(-6)mol1/kg,能完全预防体外血栓形成,IC_(50)为4.4×10~(-7)mol/kg。无论是体内或体外,都具有对抗胶原引起的血小板聚集作用,体外全对抗浓度为7.5×10~(-5)mol/L,其IC_(50)为4×10~(-5)1/L,体内剂量1.25×10~(-5)mol/kg(iv)时,血小板聚集抑制率可达60%,抗血凝的最低浓度为3 ×10~(-6)mol/L。     

示波极谱法测定片剂和尿液中别嘌醇的含量

用二阶导数示波极谱法研究了别嘌醇的测定方法。在pH5.5 HAc-NaAc缓冲溶液和0.50 mol/L H₂SO₄溶液中,浓度与波高分别在3×10^-7～1×10^-4mol/L和5×10^-7～1×10^-4mol/L内呈现良好的线性关系,检测下限分别可达8×10^-8mol/L(0.011 ppm)和3×10^-7mol/L(0.041ppm)。测定了片剂和尿液中别嘌醇的含量。初步探讨了电极反应的性质。     

前列腺素E_2及硝苯吡啶对某些免疫功能的影响

PGE_23×10~(-7)～3×10~(-6)mol/L及硝苯吡啶5×10~(-6)～1×10~(-5)mol/L对ConA诱导的淋巴细胞增殖有明显抑制作用。药物作用48h后洗去药物,加入致裂原后继续培养细胞,结果发现硝苯吡啶的抑制作用已完全逆转,而PGE_23×10~(-6)mol/L的抑制作用则部分逆转。当低浓度PGE_2(3×10~(-3)mol/L)与硝苯吡啶(1×10~(-6)mol/L)同时作用于脾细胞时,可见两者作用正巧相加,无明显拮抗与协同作用。PGE_26×10~(-6)mol/L及硝苯吡啶1×10~(-5)mol/L对巨噬细胞移动有直接抑制作用。用~(51)Cr标记调理的绵羊红细胞方法证明低浓度PGE_2对巨噬细胞吞噬功能有增强,而硝苯吡啶预培养对吞噬功能影响不大。     

Effects of septal lesions and chlordiazepoxide (Librium) on avoidance behavior in rats

The combined effects of septal lesions and chlordiazepoxide (CDP) were observed during 5 consecutive procedures involving active avoidance, and passive avoidance during approach-avoidance conflict. The Maier paradigm on a Lashley jumpingapparatus was used. The studies led to the following results and conclusions. Septal lesions had no effect on response latency in an active avoidance test. Septal lesions reduced latencies during conflict and learning tests when negative incentives were salient features. Adding CDP reduced latencies further. During extinction tests when negative incentives were withdrawn, response latency for the controls declined to that of the septal-lesioned rats. (Thus, the disinhibitory effects of septal-lesioned rats.) Thus, the disinhibitory effects of septal lesions that become manifest during passive avoidance tests, are enhanced by CDP. This suggests that the septum is not a significant site for CDP action.     

Some contextual and historical determinants of the effects of chlordiazepoxide on punished responding of rats

Abstract Rationale. A host of factors that modulate the increases produced by benzodiazepines on responding suppressed by punishment have been described. Nonetheless, the necessary and sufficient conditions for the anxiolytic-like activity in this animal model have not been fully delineated. Objectives. The present experiments sought to determine the necessity of the reinforcing event (food delivery), the role of the relationship of food delivery to the punishing stimulus, and the prevailing historical context of behavior in determining the effects of chlordiazepoxide (CDAP) from 1 to 17 mg/kg, i.p. on punished responding. Methods. Male, Sprague-Dawley rats pressed a lever under a multiple schedule. In the presence of one stimulus, every 30th response produced food and, in the presence of an alternate stimulus, every 10th response produced food, a brief electric shock, or food plus shock. Additionally, the baseline schedule was manipulated to determine antecedent experience that may contribute to the efficacy of CDAP. Results. Chlordiazepoxide generally produced little or no effect under the FR 30 schedule but increased response rates under the FR 10 schedule when responding produced either food plus shock (to 600% of control) or shock alone (300% of control) but not food alone. The increases produced when shock alone was delivered were eliminated when rats did not have a history of food plus shock pairings. In addition to increasing suppressed responding, CDAP also prevented the suppression in both punished and non-punished response rates that resulted from adding a food plus shock or shock alone contingency. Conclusions. Chlordiazepoxide and perhaps benzodiazepines in general have robust efficacy for both reducing response suppression and for preventing its occurrence. This efficacy is modulated by conditions present at the time of drug exposure and by the history of the organism with respect to response contingencies. Electronic Publication     

A critique of recent studies on placebo effects of antidepressants: importance of research on active placebos

RATIONALE: Limited published data show that drug efficacy can be influenced by stressors. Thus, drug testing in stressed animals may unravel important variables determining drug effects. OBJECTIVES: The experiments tested the anxiolytic efficacy of the benzodiazepine chlordiazepoxide under conditions of acute stress. METHODS: Previously group-housed rats were injected with 0, 3, and 10 mg/kg chlordiazepoxide, thereafter being exposed to two types of stress: novelty (transfer to an individual cage) and social defeat. Controls were group-housed animals. Anxiety was assessed on the plus maze. RESULTS: Speed of locomotion was increased by chlordiazepoxide in both stressed groups but not in controls. Chlordiazepoxide exerted a marked reduction in anxiety in controls and defeated rats but not in novelty exposed animals. The effects of novelty exposure were considerably weaker when drug testing was performed 24 h later. CONCLUSIONS: Stress exposure had an impact on the behavioral effects of chlordiazepoxide. Changes in locomotor activity induced by the drug appear to depend on the presence of a stressor, while anxiolytic efficacy appears to depend on the type of the stressor. Since it has been shown that drug efficacy changes in a variety of behavioral situations and drug classes, it is suggested that experimental background is an important variable in determining behavioral effects of drugs.     

Long-lasting reduction in ethanol selection after involuntary intake of ethanol/chlordiazepoxide

C57BL/6J mice, after having been exposed to a free-choice condition between water and aqueous chlordiazepoxide (CDP, 25 mg/100 ml) or between water and chemical ethanol/CDP, showed a significant trend for decreased preference for ethanol when tested 2 weeks later. Similarly, mice previously exposed to a no-choice intake of ethanol showed a significant decrease in ethanol preference when tested subsequently. A long-lasting (>20 weeks) reduction in ethanol selection developed after mice were previously exposed to ethanol/CDP in a no-choice condition. This was also accompanied by a decrease in the subsequent selection of ethanol/CDP, but not CDP. The exact mechanisms for the long-lasting decrease in ethanol selection was unknown, but it was not due to the development of fluid aversion. It is suggested that the combined central effects of ethanol/CDP might be partially responsible.     

Facilitating effects of chlordiazepoxide on the performance of mice in an inhibitory avoidance task

Inhibitory avoidance behaviour of mice was studied by using an automated procedure. Animals were subjected to five 15-min sessions. Facilitation of the inhibitory avoidance behaviour was observed following the administration of chlordiazepoxide at doses which did not produce significant effects on spontaneous locomotor activity.     

Effects of repeated administration of chlordiazepoxide on spontaneous locomotor activity in mice

Spontaneous locomotor activity has been studied in mice treated with single or repeated doses (five daily injections) of chlordiazepoxide. The repeated administration enhanced the stimulatory action of the lower doses of the drug, while the depressant effect of the higher doses was reduced.     

Protein synthesis and amnesia: studies with emetine and pactamycin.

Two antibiotic inhibitors of protein synthesis, emetine and pactamycin, have been tested for their effects on cerebral and peripheral protein synthesis and amnesia. Peripherally administered emetine but not pactamycin inhibited cerebral protein synthesis, although this inhibition was lower than that observed with cycloheximide or anisomycin. Pactamycin had a lesser effect on adrenal protein synthesis than emetine. This was reflected in the ability of emetine but not pactamycin to block ACTH-induced corticosteroidogenesis. Anisomycin and cycloheximide caused amnesia in a passive avoidance task, whereas pactamycin and emetine did not. These results are inconsistent with the amnesia being due to inhibition of protein synthesis in a peripheral organ. They are also inconsistent with the amnesia being due to the suppression of an adrenocortical response as previously suggested. No obvious correlation between amnesia and the mechanism of protein synthesis was observed. The most parsimonious explanation is that inhibition of cerebral protein synthesis is necessary for amnesia.     

Chlordiazepoxide and isolation induced timidity in rats

The effects of chlordiazepoxide (CDP) on emergence behavior was examined in socially reared and isolation reared rats. It was found that low doses of CDP decreased the emergence times of isolated animals but had little effect on the emergence of social animals. At higher doses the drug retarded emergence in all groups but there were no differential effects. The results do not support claims that rearing conditions influence the susceptability of rats to CNS depressants, rather they suggest that particular levels of CDP selectively influence emotional behavior.     

Chlordiazepoxide reduces discriminability but not rate of forgetting in delayed conditional discrimination

Benzodiazepine and anticholinergic drugs interfere with septo-hippocampal function in similar but not identical ways. They also share a number of common behavioural effects and, in particular, both classes of drug interfere with spatial memory in the Morris Water Maze — a test which is very sensitive to hippocampal dysfunction. We have previously shown that the anticholinergic drug scopolamine impairs discriminability, but not rate of forgetting, in delayed conditional discrimination. In the present study forgetting was quantified by fitting a negative exponential function to estimates of discriminability derived from a signal detection analysis of data from an auditory delayed conditional discrimination task. Chlordiazepoxide produced a highly significant decrease in discriminability which was monotonically related to the logarithm of dose in the range 0.67–18.0 mg/kg IP. The rate of forgetting was not increased. These data confirm the pharmacological independence of changes in discriminability and rate of forgetting; demonstrate that in this task chlordiazepoxide has similar effects to scopolamine; and suggest that the effects of chlordiazepoxide in other working memory tasks could be more a result of changed stimulus processing than impairment of memorial processes.     

Changes in the amnesic and aversive properties of avoidance conditioning with chlordiazepoxide

In two series of experiments the effects were investigated of chlordiazepoxide (CDP) upon acquisition of avoidance behavior in mice using footshock to establish an avoidance response and posttrial electroconvulsive shock (ECS) to retroactively disrupt the retention of that response. The relationship of either footshock and/or ECS during passive avoidance conditioning acquisition following prior drug treatment provided for reduced active avoidance response acquisition where such training was given following assessment of the retention of the passive avoidance behavior. The present experiments suggest that chlordiazepoxide interacts with acquired avoidance behavior such as to modify the amnesic properties of ECS. This may be due to a partial antagonism of the ECS induced retrograde amnesia, or to modification of active avoidance acquisition by drug treatment.